Method and composition for inhibiting foam in aqueous systems



Patented Sept. 30, 1952 METHOD AND COMPOSITION FOR INHIBIT- ING FOAM IN AQUEOUS SYSTEMS Lewis 0. Gunderson, Park Ridge, 111., assignor to Dearborn Chemical Company, Chicago, 111., a corporation of Illinois 1 No Drawing.

Application June 3, 1948,

Serial No. 30,981

7 Claims. (01. 252-321) This invention relates to a composition for use in conditioning water for the prevention or reduction of foaming in boilers, for the prevention or reduction of moisture entrainment in steam, for increasing the coefficient of heat transfer in boilers. cooling equipment and heat exchange systems without producing a foaming condition, and for generally improving the character of water for use in steam boilers, heat exchange systems, and the like.

' Foaming-of boiler water is not, as commonly thought, equivalent to an accumulation of foam on top of the surface of the boiler water. When steam is rapidly withdrawn from a boiler with resultant foaming, there is nowater surface withinthe'bciler correlated-with the water level indicated in the conventional water glass attachedto the boiler. In other words, there is no sharp line of demarcation between solid water and foam in the boiler during rapid steam withdrawal.

The foaming of boiler water is actually a rapid expansion of the water in the steam generating volume of water in the generatingarea is ex panded by "myriads of bubbles until the thus formedso-called light water" may fill the steam space and become entrained with the steam leav-= ing the boiler.

In other words, bubbles'need not be particularly stable to cause boiler foaming. The stability of the bubbles need be only such that the bubbles last but a very few seconds after passing the plane of the water level indicated in the water glass.

The formation of foam in an aqueous gas-liquid system may be inhibitedby the addition of a compound'containing a plurality of hydrophilic nitrogen-containing groups. The preferred compound within this classification are the acylated pclyamides. By the term .acylated polyamides I mean those compounds resulting from the addition of 1 one or more acyl groups to a compound containing a plurality of amine groups. The

polyamine may be simply hydrazine, or analkylene polyamine such as ethylene diamine or propylene diamine, a polyalkylene polyamine such asdiethylene triamine, triethylene tetramine, tetraethylene pentamine; and the like, or

I at least diacylated.

The acylating agent may be an organic acid.

halide, ester, or acid anhydride, and preferably contains at least twelve carbon atoms. Suitable .acylating agents include organic acids such as lauric, stearic, olelc, linoleic, linolenic, palmitic, and ricinoleic acid. The naphthenic acids derived from-petroleum are also valuable 'acylating agents.

Otheracylating agents that may be used the substituted acids, such as ricinoleic acidwhich has been esterified at the hydroxyl group by means of another organic acid, or an ether substituted hydroxy acid may be used as the 'acylating agent.

In general, the acylation may be carried out by simply heating one molecular proportion of" the polyamine with one or more molecular proportions of the acylating agent at a temperature of about'140 C. or higher.

Experience ha shown that steam is contami-Q nated by boiler water in spite of the action of the foam inhibitor. Investigations have proved thatsuch carryover is generally not caused by foam} development in the boiler that would reach thesteam outlet, but observations of the interiorof a boiler with strong back-lighting simulating the" dark field illumination provided in ultra microscope studies reveal that the boiler water is entrained in the steam as a dispersion of relatively" tiny droplets of boiler water in the steam space abovethe water surface. In this manner the boiler water leaves the boiler with the steam and enters the super heater units whereiri'it may cause incrustation or it may be carried over as a dried boiler water constituent to the valves and *valve bushings and cylinder packing.

contained in the boiler feedwater being forced. 'outof solution by the increased temperature. '1

The production of sucha dispersion of drop-- lets of boiler water in the steam spaceis on marily the result of a phenomenon which may be termed eflervescenee. The efiervescence phenomenon will occur from a. water surface that is not disturbed by steam bubbles and that is not covered by a layer of foam. Rather, the phenomenon is causedby the dissolved gases The effervescence causes myriads of tiny and even near-microscopic, bubbles which rise slowly through the boiler water and break more Or less violently at thesurface.

A still; more {,potent cause of eifervescence is the presence of bicarbonates in the boiler feedwater. These compounds are decomposed upon entering the boiler and mixwith the hot boiler I water, resulting in the evolutionofcarbon dioxide in the form of tiny, near microscopic bubbles which, upon rising to. the surface, burst with considerable violence to produce. adispersion of water droplets in steam that is quite stable. In

this respechthe evolution of carbon dioxide from.

the boiler water surface tends to produce more efiervescence than the liberation of dissolved air.

Boiler feedwaters normally containing a high percentage of sodium bicarbonate are especially haub ies me in; ori inatin aefferv s nce "pro-4 duced by the feedwater entering. thexboiler' below thQi'IQVQ wfithB boilenwater.surface. Y

-;.It.;-has been-observed thatj'the problem .of steam ch taminationwhich-results inxlubrication problems, uperheated-units,:incrustation, etc; is the li iighest-yduring the winter' season. .fI'his :is to: be expected, since during cold weathertwaten-can d155QlV i';mQ ZQ air .and othergases which would na ;,When;, acylatedipolyamine' foam. inhibitors: are addedotothe boiler. feedwater to inhibit foam formation in the boiler, ,rthere willbe-no foam eyerzin; the forward; part. of the boiler.- where the feedwater enters and there will be veryylittle, if;,; ,-;any,-.;,steamv bubble generation Lin 3 that area. t t1; inceptionofgthe effervescence phenomenon.

s an objector.-thisvinventions therefore, to proyide, a, compositionwhich will not onlyv inhibit the formation of foam in a boilingrwater, but will; substar1 tially; or completely inhibit the: effervesceneaofwthe hoi ler water uponiheating.

f9ammo-ns-boilingr ands-to eifervesce. on heating.-

ilemmas-ant, or Wetting agent." 'Althoughwete ting. agents 29110118 1 added: .to boiler :feediwater as .oamy producing; agentsaztheretis ".1101 su'ch .he lithey; are 1addedvi conjunction-with;

aeylated: polyamine rfoam; inhibitor-s; In fact; the i: eam inhibiting characteristics 'ofrthe. :acylated.

turally-rcontribute to, the effervescence probeven; these conditions aregmostfavorable for Obiecli'ofthe, present inventionqis to"v -method;1for-inhibiting foamingxand effervescence of aqueous. systems: which: tend to We found-thatthe. tendency of the boilerv We; r rtqreifervesce :onheating, can .bercompletely, ojr ubstantially.inhibitedrbyzthe addition: to the;

& mwate 0H9 mixture .comprisingia; surfaceactive predominantlydiydrcphilic;'acylated 13013 1,:

imnecfcam; lin-l'ribito.r and. a; surfaceetension: re-

tothe.surfacetensibmit is reasonableflt exp. t

The wetting agents contemplated by my invention include substances such as the fatty alcohol sulfates, sulfatedv fatty acid amides, sulfated fatty acid esters secondarwalcohg,snlfates, sulfated estersjofg higher molecular w'efghtalcohols and dibasic acids, alkyl aryl sulfonates, sulfonated esters of alcohols and dibasic acids, sulfonated aliphatic esters, sulfated andv sulfonated rosin -acijds-,--sulfonated aromatic ethers, the alkali metal-salts of the above, and other water.solublesulfatedor sulfona'ted organic com- I pounds. Further; non-sulfur containing organic 'compoundsm'ay be utilized as wetting agents.

These include compounds such as the partial ester "ofpolyhydric alcohols and fatty acids,

more than two polargroups. x As, indicated previously, theadd-itionlof et-- ting agent to the ,polyamide .foaminh'ibitor auses; a synergistic reaction -wherebylthe polyamides become effective in inhibitin foan' inlfboilers using feedwaters that normally do lziot respond to the foam inhibitor suchasa feed wate haying arelatively low,- contenttof. dissolved solids A very important advantage q'fg-the, propo d foam. inhibitingceomposition,lieslin the improve-1 mentinthe purity of. .steamigeneratedani with drawn from theboiler. The'm'echanism'of function whereby. the, production of a. stable dis persion of water ."droplets. in Ythe; ;st'eazn1I-is inhibit ed is not.. efinitely'.--known,. althoug I apparent .thatfa reductionin the surfacejt" sion of the boilerwater. might be ezk'pected to. sultfrorh the additionloflthe. improved mama hibiting composition to-ithe water. .-.Inasmuchilas.; the effervescencei, p enom non propertienai,

thattheobserved improvement. insteamquality;

might .be attributed. to v the reduction in; surface tension. still further. advantage,of,v the ,foamQinhihi improved (by? association with awetting: a en s);

plyammearezsin some cases improved; :possi'bly due; 'tothe action of the; wetting agent; con--.

' ditioningi-the'zsteam-":generatingr"surfaces to;-

facilitate the-adsorption? thereon of :theffoama iiihibiting:;chemical-.;j I a ;,Experimejnts.z have indicated; that: any istablec surface-tension-reducing' agent,f,.oriwetting: agent that includesa hydrocarbon? radical ;.0f;: at slea'st eleven -carb0n.'atoms and-that, in thet-c'ase :of boiler water ,orqaother aqueous systemsyis not:

precipitated; by l calciumor magnesium salts in they boiler-water: or by other ingredients con ta1ned-; .therein, and that is;eife ctive in. reducing surfacei tension ,,and increasing the wetting moi, the. heating surface by theboiler' water, increases the, efficacy, of the various; types of acylated. 75

surface-tension reducingagent is the increase the efliciency of heat transfer between :thl'e'boileiz, metal, and the-waters .Ithas rbeen.. dem'onstrated that. the use em stableJWetti-ng agent, secures dodecyl alcohol ilfateflincreases .theQCoeffibient of heat transfer; between, the. boiler, heating is faces and the boiler. waterias rmuch as v200 or; 400; percent, by actual test. However, the use of .j Wetting agent alone list impractical ibec a us'e t results vin -a great. .,-i 1'crease in. .the foaming p 7 erties-of.=the boilergwater; Theauseidflacylat d3 polyamine foam inhibitorsin, reasonable'dosagesf such as. approximately; half. the cdnceh rationlof. the, wetting .ag'ent, Qsufiices, to completely, t'f

foam formation .and'still', preserx res the beri fitQff the wetting agent 7 of boiling. when st am is generated from'thehea't: ing surfacell While ...the'.compesitions pf 'thelpre, a, tion arelparticul arlyi adapted rorlus'e'in oic motive. boiler w'aters,.theygmayt also belntiliied tems o e atin sne ai ese ieeev it?" yinaint'aining' niiclear type. v

Distearoyl ethylenediamine.

ae a rza atmospheric pressures, as in cooling systems for diesellengines, in evaporators, or in various industrial processes involving aqueous ;ornon aqueous systems where fo'amis'.aproblemt The wetting 'agents' and/or 'surface-tensiom reducing agents employed inaccordan'ce with my invention should preferably be of the type that form soluble salts or compounds with calcium and magnesium. The -wetting ability of the agents'should also be great enough preferably to decrease the surface tension of the water -by at.

settle and pack at the bottom of theboiler to cause mud burns. orotherwise interfere with the free heat transfer from the boiler metal to the water. It is also within the scope of my inven-. tion to utilize high molecularweightsurface ac; tive agents which are not strictly soluble but are colloidally dispersible in hard Water.

In addition tothe wetting agent and the foam inhibitor, otherhydrophilic agentsmay be added to assure maximum fluidityof the sludge separated out from the water by the boiling and concentration during steam generation. .Such additional agents may include hydrophilic colloids of the nature'of gum arabic, the a1ginates, including sodium alginate; seaweed colloidal ex tracts, lignin or lignin-derivatives, tannins, or any highly hydrophilic organiccolloid relatively .stable u nder boiler water conditions. Further,

basic substances such as soda ash orsodiumbicarbonate may be added to help solubilize the sludge. The small amount of bicarbonate added hasno appreciable effect on the effervescence in- 25 tannin, and the balancesoda ash. Theine' corporation of .25 partsof the above mixtureqper'z million parts water have been foundto inhibit foamformation and boiler water carryover.

f The compositions may varyover a wide range, but it is preferablel that thjef .wettingagent be present in-an amount from about one-tenth to about five times-the Weight of the foam inhibitor in the composition. A relatively higher proportion of wetting agent to acylated polyamine foam inhibitor will.-be used when the concentration of foam inhibitor is relatively high.

In general, from as little as 1 p. p. m. or less to about 50 p. p. m. of the active: foam inhibitor compounds will suffice to inhibit the foaming and efiervescence of the boiler-Water. 1

In carrying out my invention as applied to locomotive boilers, I prefer touse foam inhibitors of the following types:

Tetralauroyl triethylenetetramine. 1 Trilauroyl triethylenetetraminepp Tetralauroyltetraethylenepentamine;. a Pentalauroyltetraethylenepentarnine, U 1 Dioleoyl diethylenetriamine. Distearoyl diethylenetriamine;

6; Distearoyl hydrazine. Diricinoleoyl ethylenediamine. Diricinoleoyl diethylenetriamine. Diricinoleoyltriethylenetetramine, Tetraricinoleoyl triethylenetetramine? Triricinoleoyl tetraethylenepentamine. Disubstituted ricinoleoyl triethylenetetramine. bst t d .r inoleo l te th lene eutemi a The reaction product of 1 mol tetraethylenepentamine and at least 5 mols of capric acid. Thereaction product with 1 mol of tetraethylenepentaminewith at least l'molof castorfqil-r The reaction product of '1 moi "of "triethylenetetrainine 'and'atleasty mol of casto il polyme"rized with an unsaturatdehydr b not more than ZO'carbon atoms; The reaction product of 1 'mol of'die'thylenetr amineand 2 mols of esterified ricifioleic acid.

The reaction product of 1-mo1 of ethanol diamine and 2 mols of esterified ricinoleic acid. Distearoyl hexamethylenediamine.v f

di-isocyanateand 2 mols of lstearicacid V Thereaction product of 1 mol-of toluene'di i'socyanate and 2 mols of ricinoleic' acid. 1 The reaction product of 1mo1 of triethylene tetramine and-4 mols of naphthenic Acid .No 200). I The reactionproduct of 1 mol of .triethy lene etramine and 3 .mols of naphthenic acid fiicid No. 140). a The reaction product of 1 mol of tetraethylenepentamine and 5 mols of naphthenic acid (Acid The wet-ting iiagent and/or 'surface tension reducing agent required in the practice of'myinvention may be any commercial wetting agent that is strongly hydrophilic and stable under boiler water conditionsof temperature and alkalinity. The following examples show theclas'ses and types of compounds particularly suitable:

High molecular weight alcohol sulfates, preferably containingat least 12 carbonqatoms-peri molecule,'ie. gl, dodecyl alcoholsulfate; tetradecyl alcohol sulfate, hexadecylfalcohol-sulfate and octadecylalcohol'sulfatej Substituted long chain alcohol sulfatesh-such. as 12, ethyl ether octadecyl alcohol sul-fate ar'id 12, "octyl-ether octadecyl alcohol-sulfate:

High molecular weight sulfonic acids and Salts; such as i-lauryl sulfonate and oleoyl sulfonates as well as sulfonates of non-fatty materials such a as naphthenic acid sulfonate and alkyl aromatic.

sulfonates;

Quaternary ammonium types of wettingl ents, such asjcetyl pyridinium bromide, and octadecyl trimethyl ammonium chloride.

The compounds will normallybfei used lin: the form of their alkali metal salts. Specific compositions that may be utilized include-the following? Per cent 1 Distearoyl hydrazine 5 17H85 T "T' Qf' 17 Sodium lauryl sulfate ('Duponol ME) 2 (CB Q Q U Tannin type organic matter 20 Lignin derivative Sodium bicarbonate -1 Per cent f in water to form a s olution thatmay be fed i tolthe boiler feedwater in anyproportion.

' A r Percent Distearoyl dimethyl ammonium chloride of triethylenetetramine, which is made by condensing.triethylenetetramine with stearic acid in equimol ratios, resulting in the predominant production of the diamide. The

amide product is, thereupon, reacted with 2 mols of dimethyl sulfate to produce the quaternary compound and/or the quaternary ammoniumsaltm u 4 Triethyl cetyl'ammo'nium iodide 2 1e es (C2 5)s) r .Lignin derivative 94 i ('C HgNHC0(CH) CO- NHC12H 2,stearyl benziminazole sulphonate 2 (O17HasC oamsoms) Lignin derivative 93 Per cent The reaction product of 1 mol of triethylene tetramine and mol of soybean oil to form the amide, which is further condensed with 2 mols of acetic anhydride to form the mixed soybean acid-acetic acid amide-salt of triethylenetetramine 4 Di-octyl sodium sulfosuccinate (Aerosol OT) 2 Lignin derivative 94 To illustrate the advantage of including the wetting agent in the foam inhibiting composition, the following test was performed.

Foam inhibiting compositions were prepared by mixing 4 parts by weight of the reaction product of 1 molecular proportion of triethylenetetra- 15. I l r '1'; A composition for.inhibiting foam-formalto foam, which compositioncomprises a polytherunusing SampleB. 1 While the compositions-of this invention have my application Serial No. 305,959, now DIES. Fatmately twice that found in steam obtained during been particularly described in connection with inhibiting foam and effervescence' in boilerwater,

they also have a beneficial effect in aqueous'systems. that foamfrom causes other than boiling, such as from agitation, heating aeration and 'the like, and innoneaqueous'systems that foam or air. i I -1. 1

This a plication is a continuation-in -partajrof ent No; 2,442,768, issued June 8- 1948. ;I..claim as my invention i tion in an aqueous system havingatend'ency ito foam, which composition comprisesa'polyethylene polyamide having at least 2acyl= groups each having at least 12 carbon atoms=and=a stable, *hydrophilic surface-active *organic compound, said surface active organic. .;compound having sufficientwetting ability to decrease the-.surfabe tension of water by at least 25 =dynes1per2icentimeter when added to waterinian amount-sufficient to give a 1% solution by weight, theamourit 'c from eight ethylene polyamide having at least 2 acyl groups, each having at least 12 carbon atoms, and a stable hydrophilic surface-active organic compound se lected from the group consisting of alkali metal expand excessively due to entrained gases,- 'such' as sulfates of alcohols containing at least 12 carbon 1 atoms and alkali metal salts of organicsulfonic acids, said surface-active organic compound having suiiicient wetting ability to decrease the surface tension of water by at least 25 dynes per centimeter when added to water in an amount.

from about one-tenth to about five times by l weight of said polyethylene polyamide present.

3. A composition for inhibiting. foam formation in an aqueous system having a tendency to mine and 4 molecular proportions of naphthenic Sample A. To the other half of the mix, 49 parts.

of soda ash and 1 part sodium oleoyl sulfonate (Duponol LS) were added. The resulting composition will be designated Sample B.

Samples A and B were tested in the same 1000- motive boiler under identical conditions. Both samples were added in a concentration of 1 pound per 5000 gallons of boiler feed water.

Sample A inhibited foaming until the concentrations of dissolved solids in the boiler water reached 285 grains per gallon. Sample B, containing the added wetting agent, permitted a dissolved solids concentration of 350, grains per gal-' lon without foaming.

Steam sample taken from both runs showed that the steam generated while S ample A was present had a dissolved solids content approxifoam, which composition comprises a polyethylene polyamine having at least 3 acyl groups, each having at least 12 carbon atoms, and a stable hydrophilic surface-active organic com pound, said surface-active organic compound,

having sufiicient wetting ability to decrease the surface tension of water by at least 25 dynes per centimeter when added to water in an amount sufficient to give a 1% solution by weight, the amount of said surface-active compound being from about one-tenth to about five times by l. Acomposition for inhibiting foam formation in an aqueous system having a tendency to foam,

which composition comprises tetranaphthenoyl triethylene tetramine and sodium lauryl' sulfate,-

the amount of said sulfate being from about onetenth to about five times byweight of said I tetranaphthenoyl triethylene tetramine.

, 5. The method of inhibiting. the tendency of an aqueous system to form on boiling, which comprises dispersing into said system. a polyethylene polyamine having at least 2 acyl groups, each having atleast12 carbon atoms, and a stable,

hydrophilic surface-active organic compound, said "surface-active organic compound having sufficient wetting ability to decrease the surface weight of said polyethylene polyaminepresent.

; gtensi'on of: water :by at least; 25' dynes: Qpercen- 1 timeter when added to water'zi-n'anamountzsuificienttagive'a 1"%soluti0n :byJ-weig'ht, the vamount of said polyamine introduced being sufii'ci'ent t'o ginhibit 'thetendency OfgSfiid system'to foam. on hailing; and the amount :of'said'. surface-active sagen't being from about fie to about 5"times by weight of-ther-amount'oi' said pclyamine present.

6; The--methodof-inhibiting the: tendency of can aqueous system to foam on boiling; which comprises dispersing into said system a polyethylene polyamine having at least 3 acyl groups,

each haYins atL-ieast. 12M carbon..ammswandie stable; hydrophilic surfaceraqtive organic; (29. .1-

pound, said surface-active creams-v. compc und having, sufilcient' wettin abilitxtq decr aseethe nfaceitensi ncf; wa el: by, atlea tfligdynes. p r

,centimeten'when.addecltqiwatetcinca iquntsmfic entitp. ni v.e;a .1;%;sp1.u.t.icn;by weight; theamaunt comprises dispersing into said system. a polyethylenepolyamine havingat' least 2"acyl groups, -;-each: ha'vingat least -12 carbon'atoms, and a stable, hydrophilicsurface-active organic compound selected Iromtheg-roup consisting of a1:-

-kal-iameta1- sulfates-Tot alcohols containinglat least l ;1-2'-1carbonatoms and alkali metal salts of org"gir ieasulfonie-facids; said surface-active organic feompoundi; hayingsufficient. wetting abilityto deci ease the surface tension of water. by-at 1east"25 dynesaper centimeterwhenadded to water in an qamount sufiicient. to give a 1 fia -solution by weight, 'the amount? of? said polyamine introduced being s-ufiicient 'toinhibit the tendency of said system .--to:zfoam: on: boiling, and the amount ot 'sa-id'i surifacee'activeagenttb'eingfrom about {s te 5 times shy weig-htof said'polyamine:present.

. I WL TheamethOd; of inhibiting the tendency 0 an aqueousrsysteimtc foamy on. boiling, which of saidpn yamine. introducedfbeme,suflieient to jinhibitthe-tendency of said system to foam on boiling; and the amount of said surface-active agents-being from about 1 0' toabout 5 times by e ht; ofitheiameumref saidipolyam epxesente V ems-mess; (11131312: The following: references: are of- =record ii g the 

5. THE METHOD OF INHIBITING THE TENDENCY OF AN AQUEOUS SYSTEM TO FORM ON BOILING, WHICH COMPRISES DISPERSING INTO SYSTEM A POLYETHYLENE POLYAMINE HAVING AT LEAST 2 ACYL GROUPS, EACH HAVING AT LEAST 12 CARBON ATOMS, AND A STABLE, HYDROPHILIC SURFACE-ACTIVE ORGANIC COMPOUND, SAID SURFACE-ACTIVE ORGANIC COMPOUND HAVING SUFFICIENT WETTING ABILITY TO DECREASE THE SURFACE TENSION OF WATER BY AT LEAST 25 DYNES PER CENTTIMETER WHEN ADDED TO WATER IN AN AMOUNT SUFFICIENT TO GIVE A 1% SOLUTION BY WEIGHT, THE AMOUNT OF SAID POLYAMINE INTRODUCED BEING SUFFICIENT TO INHIBIT THE TENDENCY OF SAID SYSTEM TO FOAM ON BOILING, AND THE AMOUNT OF SAID SURFACE-ACTIVE AGENT BEING FROM ABOUT 1/10 TO ABOUT 5 TIMES BY WEIGHT OF THE AMOUNT OF SAID POLYAMINE PRESENT. 